Answer: Layer a is 500 million years old.
Explanation:
Trilobite is a member of the group of extinct arthropods found as fossils and they can be identified by the three-lobed as well as three segmented forms. These were the marine animals. These were appeared initially in the Cambrian Period. They used to live 542 million years ago so the fossils can be estimated to be aged of 500 above years old. These animals used to dominate in the sea area.
Answer and Explanation:


<em>Q1. Assume that an organism exists in which crossing over does not occur, but that all other processes associated with meiosis occur normally. Consider how the absence of crossing over would affect the outcome of meiosis.</em>
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Below are the choices:
<span>a. creating an online chat group for asking questions and posting solutions
b. establishing a standard method for delivering the results to the teacher
c. offering a wide variety of rain gauges for everyone to choose from
d. using a standard unit of measure for the duration of the study
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the answer is D. I hope it helps.
Answer:
2
Explanation:
Prokaryotic cells don't have a nucleus or membrane bound organelles
Answer:
Why does the amount or dose entering the body matter? ... A point would be reached where beneficial effects would disappear and harmful effects would start to be noticed. ... harmful is directly related to the amount of it taken into the body at one time. ... Chemicals with high toxicity only need small doses to cause poisoning.
Explanation: